And we're joined now by NPR congressional correspondent Scott Detrow. Scott, thank you so much for being here.

SCOTT DETROW, BYLINE: Hey. Good evening.

MARTIN: What sort of reaction are we hearing from Capitol Hill?

DETROW: Well, Democrats have a lot more questions. They do not think that a four-page letter from the attorney general is the end of things. You heard that from Jerrold Nadler, who's the House Judiciary Committee chairman. He says he wants Barr in front of his committee, and he wants the full report released.

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JERROLD NADLER: The attorney general's comments make it clear that Congress must step in to get the truth and provide full transparency to the American people.

DETROW: He's specifically talking about Barr's conclusion that there was no obstruction of justice based on what Robert Mueller laid out in his report. That's something echoed by House Speaker Nancy Pelosi and a lot of other Democratic leaders.

MARTIN: As we've discussed, there are a number of other investigations going on, mainly on the House side, but also one on the Senate side - the Senate Intelligence Committee. So what does this do for the larger set of investigations into the president, that total universe of investigations?

DETROW: All of those investigations are moving forward, and that includes looking at his tax returns, looking at, you know, for instance, the Trump Hotel here in Washington, D.C., and how so many lobbyists and people from foreign governments stay in it. A lot of things are moving forward. But I think one thing that really hit a roadblock today was the overall push to impeach the president that was coming from some corners of Democrats in Congress and from a lot of Democratic, you know, grassroots activists. Pelosi and other leaders all along have been saying wait for Robert Mueller's report. The fact the report is now out saying no collusion on the Russia front and inconclusive, you know, no charges obstruction of justice from the attorney general, I think that really slows down that effort.

MARTIN: But it's also true that the house speaker, Nancy Pelosi, has said just recently that she does not think impeachment was an appropriate priority for the Democrats. So given today's news, do - is there another priority that they place highly?

DETROW: Well, I think in terms of looking into the president, they are still going to do a ton of oversight. One of the main arguments from Democrats as they ran to retake the House and since they've been in control is that they feel like, for two years, Congress didn't do any of the oversight. That's a big part of its responsibility. You know, whether that's - whether that's secretaries who were forced out of the Trump administration for various scandals or a lot of these other things, that all still moves forward, not to mention the criminal investigations that are continuing in the Southern District in New York and elsewhere.

MARTIN: And we do have to mention that there's a very active and crowded presidential primary underway. How are they reacting to this news?

DETROW: By and large, they are mirroring the demands that you're hearing from Democratic leaders. Kamala Harris was campaigning in Georgia today. She said she wants Barr to testify. She wants the full report. She says, I'm not satisfied with a four-page summary from the attorney general - similar comments from other candidates as well.

Though I think it's worth pointing out, by and large, the candidates running for president have not spent a lot of time focusing on the Russia question, on the obstruction of justice question. They certainly say that President Trump is very bad for the country for a wide range of reasons, but they have not been going down the Robert Mueller road in terms of what they're focusing their campaign message on.

MARTIN: And on the other side of the question, does it seem as if the Republicans want to tie the Mueller report to the Democrats? I mean, is the argument - you see the lines emerging that this was a huge waste of time and a huge waste of money. Is that something that you see Republicans wanting to tie to the Democratic presidential contenders?

DETROW: Absolutely. I think the big argument on the Republican side so far for President Trump, Vice President Pence and others is that the Democrats are increasingly a radical party. They're being overtaken by extremists. And I think every time one of these congressional investigations goes forward or makes another subpoena request or calls another witness, the Republican response is going to be, wait a second, Robert Mueller looked into this and found nothing wrong. Why are you continuing to spend tax dollars on that?

MARTIN: And just briefly, is there going to be a big fight to get the underlying materials of this report? What does that look like?

DETROW: Absolutely. I think it's pretty clear that Barr is going to be testifying in front of Congress. I don't see him fighting his way out of that. A big chunk of this report may become public, but I can expect the White House to push back very hard on the underlying evidence coming - becoming public.